a. not suitable or right or appropriate
s. not conforming to legality, moral law, or social convention
s. not appropriate for a purpose or occasion
a. 不合适的, 错误的, 不成体统的, 不道德的
[法] 不适当的, 不合适的, 不正确的
1. The teacher said that using your phone in class is improper behavior.
老师说在课堂上使用手机是不当行为。
2. She wore an improper dress for the formal event.
她为正式活动穿了一件不合适的衣服。
3. It is improper to interrupt someone while they are speaking.
在别人说话时打断他们是不妥当的。